ISO 3133, ISO 3349, & ASTM D143 Flexural Properties of Wood

Wood is widely used as an engineering material in the construction and furniture industries. Before using a wooden beam as a building material, contractors and manufacturers need to know that the beam will hold up appropriately when subjected to the forces and environmental conditions of its end use. Bend testing is an accepted way to compare different types of wood, which is often required when choosing the appropriate material.

Materials Testing System

A typical test set up uses either Instron's 3400 or 6800 series electromechanical dual column universal testing machine configured with a 2820 series base beam and three-point anvil set. The 2820 series wood flex fixture is available in 10 kN and 50 kN capacities. In addition, a yoke deflectometer and clip-on extensometer are available for measuring bending deflections, as specified by ASTM D143.

• The different standards may have slightly different requirements, which can make complying with multiple standards a challenge to achieve. For example, ASTM D143 states that the lower support anvils of the three-point static bend fixture should be provided with bearing plates, and the load should be applied to the center of the specimen by a rigid upper block. However, ISO 3133 states that the support and load applying anvils should be rollers of a specified diameter. The modular design of the 2820 series of fixtures provides maximum flexibility by offering a range of optional anvils and four-point conversion kits, each complying with different standards.
• Recording the required amount of data points to accurately detect drops in load due to crack formation and propagation within the material. Bluehill Universal software allows the user to adjust the data sampling rate of the software up to 5 kHz in order to capture a sufficient number of data points.